The first steps towards enemy generators

[koperkapel.git] / koperkapel / scenes / base.py

diff --git a/koperkapel/scenes/base.py b/koperkapel/scenes/base.py
index 58f3874f204b87a874751d593f4360a785791a70..623eb42a977276e506449831be35956d83758d32 100644 (file)
--- a/koperkapel/scenes/base.py
+++ b/koperkapel/scenes/base.py
@@ -13,11 +13,14 @@ def apply_events(f):
 
 
 class Engine:
-    """ A holder for game state. """
+    """ A holder for game state & scene management.
+        """
 
-    def __init__(self, app, scene):
+    def __init__(self, app, scene, world):
         self._app = app
         self._scene = scene
+        self._world = world
+        self._update_vehicle = False
 
     def _apply_events(self, events):
         if not events:
@@ -26,17 +29,23 @@ class Engine:
             ev.apply(self)
 
     def change_scene(self, scene):
-        self._scene.exit()
+        self._apply_events(self._scene.exit(self._world.proxy()))
         self._scene = scene
-        self._scene.enter()
+        self._apply_events(self._scene.enter(self._world.proxy()))
+
+    def change_world(self, *args, **kw):
+        self._world.apply_event(*args, **kw)
 
     def quit_game(self):
         from pgzero.game import exit
         exit()
 
+    def move_screen(self, offset):
+        self._scene.move_screen(offset)
+
     @apply_events
     def update(self, dt):
-        return self._scene.update(dt)
+        return self._scene.update(self._world.proxy(), self, dt)
 
     def draw(self):
         self._scene.draw(self._app.screen)
@@ -81,29 +90,93 @@ class ChangeSceneEvent(Event):
     ENGINE_METHOD = "change_scene"
 
 
+class WorldEvent(Event):
+    """ Be a hero. Change the world. """
+
+    ENGINE_METHOD = "change_world"
+
+
 class QuitEvent(Event):
     """ Quit the game. """
 
     ENGINE_METHOD = "quit_game"
 
 
-class Actors:
-    """ A list of actors. """
+class MoveViewportEvent(Event):
+    """ Change to a new scene. """
 
-    def __init__(self):
-        self._actors = []
+    ENGINE_METHOD = "move_screen"
+
+
+class Layer:
+    """ A single layer of actors. """
+
+    def __init__(self, name):
+        self.name = name
+        self.actors = []
+
+    def __iter__(self):
+        return iter(self.actors)
+
+    def __getitem__(self, i):
+        return self.actors[i]
+
+    def __len__(self):
+        return len(self.actors)
 
     def add(self, actor):
-        self._actors.append(actor)
+        self.actors.append(actor)
         return actor
 
+    def clear(self):
+        self.actors.clear()
+
     def remove(self, actor):
-        self._actors.remove(actor)
+        self.actors.remove(actor)
         return actor
 
+
+class Actors:
+    """ Layers of actors.
+
+    Actors may be rendered in different layers. Layers with lower levels
+    are rendered lower than layers with higher ones.
+    """
+
+    def __init__(self):
+        self._ordered_layers = []
+        self._layers = {}
+        self.add_layer("default", 0)
+
+    def __getattr__(self, name):
+        return self._layers[name]
+
+    def add_layer(self, name, level):
+        layer = self._layers[name] = Layer(name)
+        self._ordered_layers.append((level, name))
+        self._ordered_layers.sort()
+        return layer
+
+    def add(self, actor, layer="default"):
+        return self._layers[layer].add(actor)
+
+    def remove(self, actor, layer="default"):
+        return self._layers[layer].remove(actor)
+
     def draw(self, screen):
-        for actor in self._actors:
-            actor.draw()  # TODO: allow an option screen to be passed in
+        for lvl, name in self._ordered_layers:
+            for actor in self._layers[name]:
+                # actor.draw doesn't allow blitting to anything other than
+                # the game scene
+                screen.blit(actor._surf, actor.topleft)
+
+
+def defer_to_update(f):
+    """ Defers a function until the next update run. """
+    @functools.wraps(f)
+    def wrapper(self, *args, **kw):
+        self._deferred_updates.append((f, args, kw))
+    return wrapper
 
 
 class Scene:
@@ -111,16 +184,28 @@ class Scene:
 
     def __init__(self):
         self.actors = Actors()
+        self.viewport = (0, 0)
+        self._deferred_updates = []
 
-    def enter(self):
-        pass
+    def move_screen(self, offset):
+        self.viewport = (self.viewport[0] + offset[0],
+                         self.viewport[1] + offset[1])
+
+    def calc_offset(self, x, y):
+        """ Return a position offset by the viewport. """
+        return x - self.viewport[0], y - self.viewport[1]
 
-    def exit(self):
+    def enter(self, world):
         pass
 
-    def update(self, dt):
+    def exit(self, world):
         pass
 
+    def update(self, world, engine, dt):
+        deferred_updates, self._deferred_updates = self._deferred_updates, []
+        for f, args, kw in deferred_updates:
+            f(self, world, *args, **kw)
+
     def draw(self, screen):
         screen.clear()
         self.actors.draw(screen)